Silicon oxynitride, Si.sub.2 ON.sub.2, is a refractory material of highly desireable properties for the fabrication of parts such as nozzles, turbine blades or other structural elements subjected to stress under conditions of high temperature or subjected to highly chemically active environments particularly at high temperature. Silicon oxynitride powder also has utility per se as a refractory and chemically inert material (e.g. as a powdered anti-stick coating).
Present commercial processes for making Si.sub.2 ON.sub.2 require the use of an alkaline earth metal oxide catalyst for effective conversion of the mix to a resonably high Si.sub.2 ON.sub.2 content, with a minimum of silicon nitride contamination. One such catalyzed process is disclosed in U.S. Pat. No. 3,356,513.
It is an object of the present invention to provide a method of making silicon oxynitride, of relatively high purity, which does not require the use of a catalyst.